In the figure shown, which of the following points lies within the circle?
(A)(3.5, 9.5)
*This question is included in Nova Math - Problem Set J: Coordinate Geometry, question #8

The solution is

Posted: 12/01/2015 03:31
I c, makes sense
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Posted: 12/01/2015 03:41
Hi Mohammad,

The distance of the point (-10, 1) from the origin is the square root of 101, which is slightly greater than 10. So, the point (-10, 1) is outside of the circle.

Note: The point (-10, 0) was not offered as an answer, but it would have been more tempting because its distance from the origin is 10, which puts in on the circle. But this still is not within the circle.

Nova Press
Posted: 12/02/2015 11:38
Ahhhh I c, thanks it makes sense, but just a question, did u have to try out the answers one by one to c which one works, and if I use the distance formula for each answer it can be quite time consuming
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Posted: 12/02/2015 21:47
Hi Mohammad,

Choices C and D can be rejected by inspection because the square of 10 and the square of 11 are too large by themselves.

There may be a clever way of avoiding calculating the remaining answers one-by-one, but it would probably take too long to find the trick.

Nova Press
Posted: 12/03/2015 05:25
Reply: OK, so I'll eliminate extreme choices and narrow down my search b4 the calculationa
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